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Surgery for Cubital tunnel syndrome (numbness in the ring and small fingers)

April 24th, 2007

Cubital tunnel syndrome is a condition that affects the ulnar nerve where it crosses the inside edge of the elbow. The symptoms are very similar to the pain that comes from hitting your funny bone. The ulnar nerve passes through the cubital tunnel just behind the medial epicondyle, which is the bony prominance on the medial side of the elbow. The ulnar nerve passes through the cubital tunnel and winds its way down the forearm and into the hand. It supplies feeling to the little finger and half the ring finger and controls the small muscles of the hand.

Cubital tunnel syndrome has several possible causes, but most of the time it is caused by the fact that he ulnar nerve actually stretches several millimeters when the elbow is bent. We refer to this nerve stretch as strain—and after 6-8% strain a nerve will start to have its circulation impaired. This ultimately leads to changes in the nerve, beginning with demyelination—thinning of its insulation, and ending up with atrophy of the muscles it supplies along with numbness. Sometimes the nerve will even snap over the bony medial epicondyle as the elbow is flexed. Over time, this too can cause irritation.

Numbness on the inside of the hand and in the ring and little fingers is an early sign of cubital tunnel syndrome. The numbness may develop into pain or an ache either at the elbow or on the outside of the hand. The numbness is often felt when the elbow is bent for long periods, such as when talking on the phone or while sleeping. The hand and thumb may also become clumsy as the muscles become affected. Tapping or bumping the nerve in the cubital tunnel will cause an electric shock sensation down to the little finger. This is called Tinel's sign.

When you are first evaluated I will probably order a Nerve Conduction test in order to assess the conduction velocity of the nerve and to check for evidence of muscle fibrillation—a finding that accompanies more advanced nerve injury. The early symptoms of cubital tunnel syndrome usually lessen if you just stop whatever is causing the symptoms. Anti-inflammatory medications may help control the symptoms, but it is much more important to stop doing whatever is causing the pain in the first place. Limit the amount of time you do tasks that require a lot of bending in the elbow. Take frequent breaks, and don’t lean on the inside of your elbow.
If your symptoms are worse at night, a lightweight plastic arm splint or athletic elbow pad may be worn while you sleep to limit movement and ease irritation. You can also wear the elbow pad during the day to protect the nerve from the direct pressure of leaning.

Surgical Treatment

Your symptoms may not go away, even with changes in your activities and conservative medical treatment. If symptoms persist for 3-6 months, I will often discuss surgical intervention because if symptoms are simply ignored, the problem may very well worsen, and, most importantly, the results of surgery decline as the damage to the ulnar nerve worsens.

The goal of surgery is to release the pressure on the ulnar nerve where it passes through the cubital tunnel. There are 3 common alternatives that I recommend: in situ release, in situ release with medial epicondylectomy, and in situ release with anterior subcutaneous transposition. The surgical literature does not clearly show that one operation is better than the other, but it does show, most recently, that in situ release alone is as successful as anterior transposition. Thus, the less complex in situ release alone, which does nothing to jeopardize the nerve’s blood supply and does not involve the incremental pain associated with removal of the epicondyle, has become very attractive as my 1st choice. And, patients have been very happy with its efficacy.

If the nerve subluxates either before, or after in situ release, I will recommend medial epiconylectomy, however, in order to prevent the trauma to the nerve that occurs with such snapping back and forth over the bony prominence. I will recommend an anterior transposition only if the tinel’s sign is severe, in which case, my goal is to place the nerve away from the inside of the elbow, where it will continue to be vulnerable. In my experience with over 1000 cubital tunnel releases, proper indications for surgery and expert surgical technique result in patient satisfaction in more than 90% of cases. In roughly 25% of cases, however, symptoms do not improve as much as one would hope for, and the tinel’s sign may never go away.

Cubital tunnel surgery can usually be done as an outpatient. This means you won't have to stay in the hospital overnight. Surgery can be done using a a regional anesthetic, and I will place a pain pump as well; this will help with pain relief until it is removed between 4 and 7 days after your operation. After surgery you'll have a soft bandage wrapped from your hand to your armpit, and you will not be able to drive for 1-2 weeks. At 4-7 days after surgery the dressing will be removed and you will work on range of motion. You just need to be careful to avoid doing too much, too quickly. At about 6-8 weeks, you'll start doing more active strengthening. It may take 3 or so months to feel better, and full recovery of the nerve may take 1 year.

Related Photos:

Anatomy of the cubital tunnel

Ulnar nerve sensory distribution

The roof of the cubital tunnel may be too tight with elbow flexion. In situ release may be sufficient to allow slight anterior movement with flexion, thereby diminishing nerve strain

In situ release has been performed

The ulnar nerve is scarred in the cubital tunnel prior to anterior transposition

Anterior subcutaneous transposition has been performed

Ulnar nerve subluxation over top of the medial epicondyle accompanies flexion

Medial epiconylectomy has been performed

After flexor-pronator closure, the ulnar nerve is no longer prevented from moving anteriorly by the epicondyle during elbow flexion

Related Videos:

Ulnar nerve subluxation with elbow flexion-extension may lead to cubital tunnel syndrome
Early outcome after in situ ulnar nerve release alone. This procedure is contraindicated if nerve subluxation is noted.